Project description

This package provides a simple statistical profiler for Python.

Python’s default profiler has been lsprof for several years. This is
an instrumenting profiler, which means that it saves data on every
action of interest. In the case of lsprof, it runs at function entry
and exit. This has problems: it can be expensive due to frequent
sampling, and it is blind to hot spots within a function.

In contrast, statprof samples the call stack periodically (by
default, 1000 times per second), and it correctly tracks line numbers
inside a function. This means that if you have a 50-line function
that contains two hot loops, statprof is likely to report them both
accurately.

Note

This package does not yet work on Windows! See the
implementation and portability notes below for details.

How to get it

Use pip!

pip install statprof-smarkets

Warning: it uses statprof as Python module name so this will conflict with
original statprof installation if present.

Portability

Because statprof uses the Unix itimer signal facility, it does not
currently work on Windows. (Patches to improve portability would be
most welcome.)

Implementation notes

The statprof profiler works by setting the Unix profiling signal
ITIMER_PROF to go off after the interval you define in the call to
reset(). When the signal fires, a sampling routine is run which
looks at the current procedure that’s executing, and then crawls up
the stack, and for each frame encountered, increments that frame’s
code object’s sample count. Note that if a procedure is encountered
multiple times on a given stack, it is only counted once. After the
sampling is complete, the profiler resets profiling timer to fire
again after the appropriate interval.

Meanwhile, the profiler keeps track, via os.times(), how much CPU
time (system and user – which is also what ITIMER_PROF tracks), has
elapsed while code has been executing within a start()/stop()
block.

The profiler also tries (as much as possible) to avoid counting or
timing its own code.

History

This package was originally written and released by
Andy Wingo.
It was ported to modern Python by Alex Frazer, and posted to GitHub by
Jeff Muizelaar. Maintained by Bryan O’Sullivan, was forked by
Smarkets due to package not being maintaned anymore.